1. Field of the Invention
The present invention relates to an imaging apparatus.
Priority is claimed on Japanese Patent Application No. 2013-186471, filed Sep. 9, 2013, the content of which is incorporated herein by reference.
2. Description of Related Art
In the imaging of an imaging apparatus, such as a digital camera, a process such as a spatial filtering process is performed on a signal of each pixel (hereinafter, referred to as a “pixel signal”) output from a solid-state imaging device provided in the imaging apparatus. In general, the solid-state imaging device performs a raster scan of pixels, and sequentially outputs pixel signals in a horizontal direction of the image. When performing a spatial filtering process directly on the pixel signals that are output as described above, an image-processing device that is provided in the imaging apparatus and performs the spatial filtering process needs to include a line memory that temporarily stores pixel signals in a horizontal direction (lateral direction), which are output from the solid-state imaging device, by the number of rows required for the spatial filtering process (refer to FIGS. 9A and 9B).
For example, as shown in FIG. 9A, when performing the spatial filtering process on “3×3” pixels of an image, the image-processing device processes image data of “3 rows×3 columns” simultaneously. Therefore, as shown in FIG. 9B, the image-processing device needs to include two line memories in which pixel signals in the horizontal direction of the image are stored by one row. FIGS. 9A and 9B show an example of the configuration including two line memories (each for 6000 pixels) corresponding to an image having a horizontal width (image size in the horizontal direction) of 6000 pixels.
In the imaging apparatus in recent years, as the number of pixels of the solid-state imaging device has increased with an increase in the resolution of an image to be captured, the number of pixels in the horizontal direction of the solid-state imaging device has also increased every year. For this reason, in the image-processing device, the storage capacity of each line memory increases according to the corresponding number of pixels in the horizontal direction in the spatial filtering process. The increase in the storage capacity of each line memory in the image-processing device causes an increase in the circuit size of the imaging apparatus.
For example, in the configuration shown in FIG. 9B, a case of an image having a horizontal width of 10000 pixels is considered. In this case, it is possible to correspond to an image which has a horizontal image size of 10000 pixels by setting the storage capacity of each line memory to 10000 pixels. However, if the storage capacity of the line memory is set to 10000 pixels, the circuit size is increased by the increased amount.
Therefore, for example, Japanese Patent (Granted) Publication No. 4179701 discloses a technique of an image-processing device that performs image processing on one image a multiple of times. In the technique disclosed in Japanese Patent (Granted) Publication No. 4179701, pixel signals output from a solid-state imaging device are temporarily stored in a frame memory provided outside the image-processing device, and then image processing is performed multiple times while reading pixel signals required for processing from the frame memory, thereby generating one image. That is, in the technique disclosed in Japanese Patent (Granted) Publication No. 4179701, one image is divided into a plurality of blocks, and image processing is performed by the same number of times as the number of divided blocks, thereby generating one image.